Guide extension catheter assemblies, systems and methods of use

ABSTRACT

A guide extension catheter assembly including a guide extension catheter and a support device. The guide extension catheter includes a shaft and a tubular member. The support device includes a push member and a shuttle member. The guide extension catheter assembly is configured to selectively provide a delivery state in which at least a portion of the shuttle member is disposed within the lumen, a leading end of the shuttle member is distal a distal end of the tubular member, and the shuttle member is directly, physically connected to the tubular member. In the delivery state, a longitudinal distal force applied to the push member is transferred to the tubular member as a longitudinal distal force via the shuttle member. The guide extension catheter assemblies of the present disclosure can promote a two stage guide extension catheter deployment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Non-Provisional patent application claims the benefit of the filingdate of U.S. Provisional Application Ser. No. 62/720,670 filed Aug. 21,2018, the entire teachings of which are incorporated herein byreference.

FIELD

Aspects of the present disclosure relate to guide catheter systems foraccessing intravascular target sites, guide extension catheters usefulwith such systems, and methods of use thereof.

BACKGROUND

Arteries of the heart, and more specifically coronary arteries, maysometimes be occluded or narrowed by atherosclerotic plaques or otherlesions. These afflictions are generally referred to as coronary heartdisease or stenosis, and result in inadequate blood flow to distalarteries and tissue. Heart bypass surgery may be a viable surgicalprocedure for certain patients suffering from coronary heart disease.However, traditional open heart surgery may inflict significant patienttrauma and discomfort, and may require extensive recuperation times.Further, life threatening complications may occur due to the invasivenature of the surgery and the necessity for stoppage of the heart duringsuch a surgery.

To address these concerns, efforts have been made to performinterventional cardiology procedures using minimally invasivetechniques. In an example, percutaneous transcatheter (or transluminal)delivery and implantation of interventional coronary device are employedto overcome the problems presented by traditional open heart surgery. Insuch a procedure, a guide catheter is first interested through anincision into a femoral (transfemoral) or radial (transradial) artery ofa patient. For example, the Seldinger technique may be utilized ineither method for percutaneously introducing the guide catheter. In suchmethods, the guide catheter is advanced through the aorta and insertedinto the opening of an ostium of a coronary artery. A guidewire, orother interventional coronary device, such as a catheter-mounted stentand/or balloon catheter, may be introduced through the guide catheterand maneuvered/advanced through the vasculature and the stenosis of thediseased coronary artery. However, when attempting to pass through adifficult stenosis, or when conducting a radial intervention using asmall diameter guide catheter, the guide catheter may not have adequateback support, and continued application of force to advance theinterventional coronary device through the stenosis may cause the distalend of the guide catheter to dislodge from the opening of the ostium ofthe coronary artery, resulting in potential damage to the surroundingtissue.

In order to prevent the guide catheter from dislodging, interventionalcardiologists sometimes would deep seat the guide catheter into thecoronary artery. The term “deep seat” or “deep seating” means that theguide catheter would be pushed farther downstream into the coronaryartery. However, deep seating the guide catheter may risk the guidecatheter damaging the coronary artery wall (e.g., dissection orrupture), occluding the coronary artery, or interfering with blood flowto the coronary artery.

One attempt to provide additional support to a guide catheter that hasgained acceptance is the use of a guide extension catheter. The guideextension catheter is deployed within a lumen of the guide catheter andextends distally from the distal end of the guide catheter into thecoronary artery. Their smaller size, as compared to the guide catheter,allows the guide extension catheter to be seated more deeply in thecoronary artery with less potential damage. The guide extension catheterprovides additional support to the guide catheter to aid in delivery ofinterventional coronary devices. In cases with a difficult stenosis orradial interventions, the use of the guide extension catheter may reducethe risk of the guide catheter dislodging from the opening of the ostiumof the coronary artery during treatment.

SUMMARY

Some aspects of the present disclosure related to a guide extensioncatheter assembly including a guide extension catheter and a supportdevice. The guide extension catheter includes a shaft and a tubularmember. The tubular member defines a proximal end opposite a distal end,and a lumen open to the proximal and distal ends. The shaft is coupledto the tubular member at the proximal end and extends proximally fromthe proximal end. The support device includes a push member and ashuttle member. The shuttle member defines a leading end opposite atrailing end. The push member is coupled to the shuttle member at thetrailing end and extends proximally from the trailing end. The guideextension catheter assembly is configured to selectively provide adelivery state in which at least a portion of the shuttle member isdisposed within the lumen, the leading end is distal the distal end, andthe shuttle member is directly, physically connected to the tubularmember. In the delivery state, a longitudinal distal force applied tothe push member is transferred to the tubular member as a longitudinaldistal force via the shuttle member. The guide extension catheterassemblies of the present disclosure can promote a two stage guideextension catheter deployment; the shuttle member promotes delivery ofthe tubular member and can then be removed with the tubular member thenfacilitating guide extension catheter procedures. In some embodiments,the guide extension catheter assembly includes complementary connectionfeatures that selectively provide direct, physical connection betweenthe tubular member and the shuttle member. In some embodiments, thetubular member defines a plurality of perfusion holes and/or otherfeatures conducive to guide extension catheter procedures.

Other aspects of the present disclosure are directed toward a coronarytreatment system including a guide catheter, a guide extension catheterassembly, and an interventional coronary device. The guide extensioncatheter assembly includes a guide extension catheter and a supportdevice. The guide extension catheter includes a shaft and a tubularmember. The tubular member defines a proximal end opposite a distal end,and a lumen open to the proximal and distal ends. The shaft is coupledto the tubular member at the proximal end and extends proximally fromthe proximal end. The support device includes a push member and ashuttle member. The shuttle member defines a leading end opposite atrailing end. The push member is coupled to the shuttle member at thetrailing end and extends proximally from the trailing end. The guideextension catheter assembly is configured to selectively provide adelivery state in which at least a portion of the shuttle member isdisposed within the lumen, the leading end is distal the distal end, andthe shuttle member is directly, physically connected to the tubularmember. In the delivery state, a longitudinal distal force applied tothe push member is transferred to the tubular member as a longitudinaldistal force via the shuttle member. In some embodiments, the guidecatheter defines a lumen through sized to slidably receive the tubularmember and the shuttle member in the delivery state, as well as aworking end of the interventional coronary device. In other embodiments,the system further includes a guidewire in addition to theinterventional coronary device.

Yet other aspects of the present disclosure are directed toward methodsof percutaneously accessing an intravascular target region. The methodsinclude positioning a distal side of a guide catheter adjacent to anostium of a target vessel. A guide extension catheter assembly isarranged to a delivery state. The guide extension catheter assemblyincludes a guide extension catheter and a support device. The guideextension catheter includes a shaft and a tubular member. The tubularmember defines a proximal end opposite a distal end, and a lumen open tothe proximal and distal ends. The shaft is coupled to the tubular memberat the proximal end and extends proximally from the proximal end. Thesupport device includes a push member and a shuttle member. The shuttlemember defines a leading end opposite a trailing end. The push member iscoupled to the shuttle member at the trailing end and extends proximallyfrom the trailing end. The delivery state includes at least a portion ofthe shuttle member disposed within the lumen, the leading end distal thedistal end, and the shuttle member directly, physically connected to thetubular member. In the delivery state, a longitudinal distal forceapplied to the push member is transferred to the tubular member as alongitudinal distal force via the shuttle member. The guide extensioncatheter assembly is advanced in the delivery state through the guidecatheter such that at least a region of the tubular member projectsdistally beyond the distal side of the guide catheter. The guideextension catheter assembly is transitioned from the delivery state,including removing the support device from the guide extension catheter.An interventional coronary device (e.g., a catheter-based devicecarrying a stent) is then advanced through the guide catheter and thetubular member. In some embodiments, the methods further include used ofa guidewire to direct one or more of the guide catheter and the guideextension catheter assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded side view of a guide extension catheter assemblyin accordance with principles of the present disclosure;

FIG. 1B is a side view of the guide extension catheter assembly of FIG.1A in a delivery state;

FIG. 2 is an enlarged cross-sectional view of a tubular member componentof a guide extension catheter of the guide extension catheter assemblyof FIG. 1A, taken along the line 2-2;

FIG. 3 is a simplified side view of an alternative tubular member usefulwith the guide extension catheter assemblies of the present disclosure;

FIG. 4 is an enlarged cross-sectional view of a shuttle member componentof a support device of the guide extension catheter assembly of FIG. 1A,taken along the line 4-4;

FIG. 5A is an enlarged, longitudinal cross-sectional view of a portionof the support device of FIG. 1A;

FIG. 5B is an enlarged, longitudinal cross-sectional view of a portionof another support device useful with the guide extension catheterassemblies of the present disclosure;

FIG. 6 is an enlarged cross-sectional view of the guide extensioncatheter assembly in the delivery state of FIG. 1B, taken along the line6-6;

FIG. 7A is an enlarged cross-sectional view of a portion of the guideextension catheter assembly in the delivery state of FIG. 1B;

FIG. 7B is an enlarged cross-sectional view of a portion of anotherguide extension catheter assembly in a delivery state in accordance withprinciples of the present disclosure;

FIG. 7C is an enlarged side view of a portion of another guide extensioncatheter assembly in a delivery state in accordance with principles ofthe present disclosure; and

FIGS. 8A-8E illustrate methods of percutaneously accessing anintravascular target region in accordance with principles of the presentdisclosure, including methods of using a coronary treatment systemincluding a guide extension catheter assembly.

DETAILED DESCRIPTION

Specific embodiments of the present disclosure are now described withreference to the figures, wherein like reference numbers indicateidentical or functionally similar elements. The terms “distal” and“proximal” are used in the present disclosure with respect to a positionor direction relative to the treating clinician. “Distal” or “distally”refer to positions distant from or in a direction away from theclinician. “Proximal” and “proximally” refer to positions near or in adirection toward the clinician.

One embodiment of a guide extension catheter assembly 20 in accordancewith principles of the present disclosure and useful with systems andmethods of the present disclosure is shown in FIGS. 1A and 1B, andincludes a guide extension catheter 30 and a support device 32. Detailson the various components are provided below. In general terms, theguide extension catheter 30 includes a tubular member 40, and thesupport device 32 includes a shuttle member 42. In a delivery state ofthe guide extension catheter assembly 20 reflected by FIG. 1B, theshuttle member 42 is disposed within the tubular member 40, and canpromote delivery or advancement of the guide extension catheter assembly20 through a tortuous path (e.g., vasculature). Once a desired locationhas been attained, the shuttle member 42 can be removed from the tubularmember 40, and the guide extension catheter 30 is available for otherprocedural steps. For example, the tubular member 40 can serve as anextension of a conventional guide catheter. With some guide extensioncatheter assemblies 20 of the present disclosure, attributes conduciveto intravascular traversal can be incorporated into a design of thesupport device 32 (e.g., hoop strength, longitudinal push strength,etc.), whereas attributes conducive to guidance and delivery of aninterventional coronary device (not shown) can be incorporated into adesign of the guide extension catheter 30. In some embodiments,complementary connection features are provided that provide direct,physical connection between the tubular member 40 and the shuttle member42 in the delivery state as described below.

The guide extension catheter 30 can assume various forms, and includesthe tubular member 40 and a shaft 50. As described below, the shaft 50is coupled to, and extends proximally from, the tubular member 40. As apoint of reference, in some non-limiting embodiments the guide extensioncatheter 30 can have a length on the order of 150 centimeters (cm), withthe tubular member 40 being approximately 20-40 cm in length. However,this is not meant to limit the present disclosure, and the guideextension catheter 30 and/or the tubular member 40 thereof may be longeror shorter.

With reference between FIGS. 1A and 2, the tubular member 40 defines aproximal end 52 opposite a distal end 54, and a lumen 56 open at theproximal and distal ends 52, 54. The lumen 56 is sized to receive adevice, such as an interventional coronary device (not shown) asdescribed below, for guiding the device along a longitudinal axis A ofthe tubular member 40. Further, an outer diameter ODT of the tubularmember 40 can be selected in accordance with a desired end use asdescribed below (e.g., the outer diameter ODT can be selected such thatthe tubular member 40 can be slidably received within a guide catheterbeing employed with a particular end use procedure).

The tubular member 40 can be formed of various materials, non-limitingexamples of which include polymers and braided polymers. In therepresentation of FIG. 2, a structure of the tubular member 40 isillustrated as being defined by a wall 58. The wall 58 can have ahomogenous or monolithic construction as shown. In other embodiments,the wall 58 can be collectively formed by two or more continuous ordiscontinuous layers (e.g., an inner liner and outer jacket sandwichingone or more wires or other reinforcement bodies). Regardless, the wall58 has a wall thickness TT and provides the tubular member 40 withphysical attributes including hoop strength and longitudinal columnrigidity or stiffness (i.e., extent to which the tubular member 40resists deformation when subjected to a force along the longitudinalaxis A).

In some embodiments, the tubular member 40 can be designed toincorporate attributes conducive to use of the tubular member 40 as anextension of a conventional guide catheter; in related embodiments, adesign of the tubular member 40 need not directly account for orconsider deliverability through a tortuous intravascular path (e.g., thetubular member 40 does not need to have or exhibit a hoop strengthand/or longitudinal column rigidity normally considered necessary forintravascular delivery) due to provision of the support device 42 asdescribed below. Thus, in some embodiments, the wall thickness TT can beless than the wall thickness conventionally employed with guideextension catheters. Along these same lines, FIG. 3 illustrates anothertubular member 40′ useful with the assemblies, systems and methods ofthe present disclosure. The tubular member 40′ is akin to the tubularmember 40 (FIG. 1A) described above, and includes the wall 58. Inaddition, a plurality of perfusion holes 60 are defined by or formed inthe wall 58. The perfusion holes 60 can have wide variety of shapes andsizes, and can be formed in a number of different patterns. In generalterms, the perfusion holes 60 are open to the lumen 56 (FIG. 2) and areconfigured to aid in continuous perfusion during use of the tubularmember 40′ as an extension of a conventional guide catheter. Althoughpresence of the perfusion holes 60 might otherwise negatively affectdeliverability of the tubular member 40′ as a standalone device, thesupport device 32 (FIG. 1A) serves to facilitate delivery of the tubularmember 40′. Other features can be incorporated into the tubular member40′ that enhance performance as an extension of a conventional guidecatheter.

Returning to FIGS. 1A and 1B, the shaft 50, also referred to as apushwire or push member, defines a proximal side 60 opposite a distalside 62. The distal side 62 is coupled to the tubular member 40 in aregion of the proximal end 52, and the shaft 50 is arranged to extendproximally from the tubular member 40 to the proximal side 60. The shaft50 may be formed of materials such as, but not limited to, stainlesssteel, nickel-titanium alloys (e.g., NITINOL), high performance alloysthat are cobalt, chromium, molybdenum and/or nickel based (e.g., MP35N,L605, ELGILOY), or other materials suitable for the purposes describedherein.

In some embodiments, the shaft 50 can be a solid body (e.g., a solidwire). In other embodiments, an internal passage can be defined along aportion or an entirety of the shaft 50. In some embodiments, the shaft50 can have a uniform cross-sectional shape (e.g., circular, square,etc.) from the proximal side 60 to the distal side 62. In otherembodiments, one or more variations in cross-sectional shape can beincorporated into the shaft 50 along a length thereof (e.g., the shaft50 can have a varying thickness, the shaft 50 can have a more flattenedshape proximate the tubular member 40, etc.). Regardless, a maximumouter dimension ODSHAFT of the shaft 50 is less than the outer diameterODT (FIG. 2) of the tubular member 40.

Coupling of the shaft 50 with the tubular member 40 can assume variousforms appropriate for providing a robust connection. For example, insome non-limiting embodiments, a segment of the shaft 50, including thedistal side 62, can be embedded into a thickness of the tubular member40. Alternatively, the shaft 50 can be secured (e.g., bonded) to anexterior or interior surface of the tubular member 40. In yet otherembodiments, a connecting member (not shown) can be provided thatsecures the shaft 50 relative to the tubular member 40. For example, theshaft 50 can be attached to a collar that in turn is secured over anexterior of the tubular member 40.

With specific reference to FIG. 1A, the support device 32 can assumevarious forms, and includes the shuttle member 42 and a push member 70.As described below, the push member 70 is coupled to, and extendsproximally from, the shuttle member 42. As a point of reference, in somenon-limiting embodiments the support device 32 can have a length on theorder of 150 cm, with the shuttle member 42 being approximately 20-40 cmin length (and optionally slightly longer than the tubular member 40.However, this is not meant to limit the present disclosure, and thesupport device 32 and/or the shuttle member 42 thereof may be longer orshorter.

With reference between FIGS. 1A and 4, the shuttle member 42 defines aleading end 72 opposite a trailing end 74, and a passageway 76(referenced generally in FIG. 1A). The passageway 76 is sized to receivea device, such as guidewire (not shown) as described below, and can beopen to an exterior of the shuttle member 42 at the leading end 72 andin a region of the trailing end 74 for guiding the device along alongitudinal axis B of the shuttle member 42.

The shuttle member 42 can be a continuous, homogenous body in someembodiments. In other embodiments, the shuttle member 42 can include twoor more sections that are separately formed and subsequently assembled.Regardless, an interface region 80 of the shuttle member 42 includes,and extends proximally from, the leading end 72. The interface region 80has a length (i.e., dimension in a direction parallel with thelongitudinal axis B) that is not less than a length of the tubularmember 40, and defines a maximum outer dimension (e.g., outer diameter)ODs in a direction transverse to the longitudinal axis B. The maximumouter dimension ODs corresponds with (e.g., is slightly less than) asize or diameter of the tubular member lumen 56 (FIG. 2) such that theinterface region 80 is configured to be readily received within thetubular member 40. In some embodiments, one or more portions of theshuttle member 42 proximal the interface region 80 can have an outerdimension greater than the maximum outer dimension ODs as describedbelow. With these and similar constructions, however, the maximum outerdimension ODs can be identified along the shuttle member 42 from theleading end 72 to a location not less than a length of the tubularmember 40. In other embodiments, an entirety of the shuttle member 42has a maximum outer dimension approximating (e.g., slightly less than) asize or diameter of the tubular member lumen 56.

In some embodiments, the interface region 80 includes or is defined by asupport section 82 and an optional tip section 84. The support section82 is configured to receive and support the tubular member 40. Forexample, the support section 82 has a length (i.e., dimension in adirection parallel with the longitudinal axis B) that is not less than alength of the tubular member 40, and has a substantially uniform (i.e.,within 10 percent of a truly uniform construction) exterior shape andsize in a direction of the length of the shuttle member 42. In someembodiments, the support section 82 can define a circular exterior shapein transverse cross-section as shown in FIG. 4, although other shapesare acceptable. Regardless, the support section 82 defines the maximumouter dimension (e.g., outer diameter) ODs.

The support section 82, optionally an entirety of the shuttle member 42,can be formed of various materials, non-limiting examples of whichinclude polymers (e.g., thermoplastic elastomer such as a polyetherblock amide thermoplastic elastomer available from Arkema of Colombes,FR under the tradename PEBAX®) and braided polymers. In therepresentation of FIG. 4, a structure of the support section 82 isillustrated as being defined by a wall 86. The wall 86 can have ahomogenous or monolithic construction as shown. In other embodiments,the wall 86 can be collectively formed by two or more continuous ordiscontinuous layers (e.g., an inner liner and outer jacket sandwichingone or more wires or other reinforcement bodies). Regardless, the wall86 has a wall thickness Ts and provides the shuttle member 42 withphysical attributes including hoop strength and longitudinal columnrigidity or stiffness (i.e., extent to which the shuttle member 42resists deformation when subjected to a force along the longitudinalaxis B). In some embodiments, the shuttle member 42, and in particularat least the support section 82, incorporates one or more features orattributes that render the shuttle member 42 more conducive tointravascular delivery as compared to the tubular member 40. Forexample, in some embodiments, the wall thickness Ts of the shuttlemember 42 (at least along the support section 82) is greater than thewall thickness TT (FIG. 2) of the tubular member 40, for example atleast 50% greater. Alternatively or in addition, a hoop strength of theshuttle member 42 along at least the support section 82 can be greaterthan the hoop strength of the tubular member 40, for example at least50% greater. Alternatively or in addition, a longitudinal columnrigidity or stiffness (i.e., extent to which the shuttle member 42resists deformation when subjected to a force along the longitudinalaxis B) of the shuttle member 42 along at least the support section 82can be greater than the longitudinal column rigidity or stiffness of thetubular member 40. While the support section 82 is generally illustratedas having a shape akin to the shape of the tubular member 40 (e.g.,circular shape in transverse cross-section), other formats are alsoacceptable. For example, an outer or perimeter shape of the supportsection 82 in transverse cross-section can include one or more linearsegments (e.g., square, hexagonal, etc.), can have an irregular shape,etc.

Where provided, the tip section 84 tapers in the proximal direction fromthe support section 82 to the leading end 72, such that the tip section84 promotes atraumatic interface with tissue. The atraumatic attributesof the tip section 84 can be further enhanced by forming the tip section84 from a material differing from that of the support section 82; forexample, a material of the tip section 84 can be a softer and/or morecompliant than a material of the support section 82. In otherembodiments, the shuttle member 42 need not include a tapered tip (e.g.,the leading end 72 has the maximum outer dimension ODs).

Regardless of whether the shuttle member 42 includes a tapered tip, insome non-limiting embodiments, the shuttle member 42 can optionallyfurther include or define a trailing region 90 extending proximally fromthe interface region 80. The trailing region 90 may have an exteriorsize and/or shape differing from that of the interface region 80, and inparticular differing from the support section 82 (e.g., a portion of thetrailing region 90 can have an outer dimension or diameter greater thanthe maximum outer dimension ODs of the support section 82, can taperdistally to the trailing end 74, etc.).

The push member 70, also referred to as a pushwire or a shaft, defines aleading side 100 opposite a trailing side 102. The leading side 100 iscoupled to the shuttle member 42 in a region of the trailing end 74, andthe push member 70 is arranged to extend proximally from the shuttlemember 42 to the trailing side 102. The push member 70 may be formed ofmaterials such as, but not limited to, stainless steel, nickel-titaniumalloys (e.g., NITINOL), high performance alloys that are cobalt,chromium, molybdenum and/or nickel based (e.g., MP35N, L605, ELGILOY),or other materials suitable for the purposes described herein.

In some embodiments, the push member 70 can be a solid body (e.g., asolid wire). In other embodiments, an internal passage can be definedalong a portion or an entirety of the push member 70. In someembodiments, the push member 70 can have a uniform cross-sectional shape(e.g., circular, square, etc.) from the leading side 100 to the trailingside 102. In other embodiments, one or more variations incross-sectional shape can be incorporated into the push member 70 alonga length thereof (e.g., the push member 70 can have a varying thickness,the push member 70 can have a more flattened shape proximate the shuttlemember 42, etc.). Regardless, a maximum outer dimension ODR of the pushmember 70 is less than the maximum outer dimension ODs of the shuttlemember 42.

Coupling of the push member 70 with the shuttle member 42 can assumevarious forms appropriate for providing a robust connection. Forexample, in some non-limiting embodiments, a segment of the push member70, including the leading edge 100, can be embedded into the shuttlemember 42. Alternatively, the push member 70 can be secured (e.g.,bonded) to an exterior or interior surface of the shuttle member 42. Inyet other embodiments, a connecting member (not shown) can be providedthat secures the push member 70 relative to the shuttle member 42. Forexample, the push member 70 can be attached to a collar that in turn issecured over an exterior of the shuttle member 42 (with the collaroptionally being considered as a part or component of the shuttle member42 (e.g., the trailing region 90)).

The push member 70 can be arranged relative to the shuttle member 42 invarious manners. For example, FIG. 5A illustrates that in somenon-limiting embodiments, the push member 70 can be approximatelycentered with or axially aligned with the shuttle member 42. FIG. 5Afurther reflects that with these and other embodiments, the passageway76 can be non-linear across a length of the shuttle member 72. Anotherexample support device 32′ is shown in FIG. 5B and includes a shuttlemember 42′ and a push member 70′ akin to the descriptions above. Theshuttle member 42′ defines a passageway 76′ (e.g., for slidablyreceiving a guidewire (not shown) that is linear across a length of theshuttle member 42′. The push member 70′ extends proximally from theshuttle member 42′ and is off-set from central or longitudinal axis ofthe shuttle member 42′. Other relationships between the shuttle member42′, the push member 70′ and the passageway 76′ are also envisioned.

The guide extension catheter assembly 20 is transitioned to the deliverystate of FIG. 1B by directing the leading end 72 of the shuttle member42 into the lumen 56 (FIG. 2) of the tubular member 40 at the proximalend 52. The shuttle member 42 is then advanced distally relative to thetubular member 40 (and/or the tubular member 40 retracted proximallyrelative to the shuttle member 42), locating a length of the tubularmember 40 over the shuttle member 42. Advancement and/or manipulation ofthe tubular member 40 and the shuttle member 42 relative to one anothercontinues until the delivery state arrangement is achieved in which theleading end 72 of the shuttle member 42 is distal the distal end 54 ofthe tubular member 40, and the shuttle member 42 is directly, physicallyconnected to the tubular member 40. In the delivery state, alongitudinal distal force applied to the push member 70 is transferredto the tubular member 40 as a longitudinal distal force via the shuttlemember 42. As described in greater detail below, in some embodiments thetubular member 40 and the shuttle member 42 incorporate complimentaryconnection features that provide the direct, physical connection. Thus,in some embodiments and as reflected in FIG. 6, the tubular member 40may be generally disposed over the shuttle member 42 but with sufficientclearance to allow for relatively easy withdrawal of the shuttle member42 from the tubular member 40 when desired; with these and otherembodiments, the complementary connection features provide the direct,physical connection between the tubular member 40 and the shuttle member42 in a manner that provides an at least one directional “lock” betweenthe tubular member 40 and the shuttle member 42 (e.g., in the deliverystate, the tubular member 40 and the shuttle member 42 are lockedrelative to one another such that the shuttle member 42 cannot befurther distally advanced relative to the tubular member 40 from thearrangement of FIG. 1B). Regardless, in the delivery state, the shuttlemember 42 supports the tubular member 40, providing physical and/ormechanical properties that promote ease of intravascular deliverability(and which physical and/or mechanical properties are not fully providedby the tubular member 40 in and of itself).

FIG. 7A depicts the tubular member 40 and the shuttle member 42 arrangedin the delivery state, and further illustrates one example ofcomplementary connection features in accordance with principles of thepresent disclosure. In particular, the shuttle member 42 includes orcarries a shoulder 120, and the proximal end 52 of the tubular member 40is sized and shaped to abut the shoulder 120 with distal insertion ofthe shuttle member 42 through the lumen 56. For example, an outerdimension or diameter of the support section 82 of the shuttle member 42can approximate or be slightly less than a diameter of the lumen 56; theshoulder 120 extends radially outward from the support section 82 to anouter diameter greater than the diameter of lumen 56 and approximatingan outer diameter of the tubular member 40. In the delivery state, theshoulder 120 directly, physically contacts the proximal end 52 toachieve or provide a direct, physical connection between the tubularmember 40 and the shuttle member 42 in distal direction of the shuttlemember 42 relative to the tubular member 40. That is to say, the direct,physical connection provided by the complementary connection features ofthe embodiment of FIG. 7A is such that a longitudinal distal forceapplied to the push member 70 is directly transferred onto the tubularmember 40 as a distal longitudinal force via the abutting interfacebetween the proximal end 52 of the tubular member 40 and the shoulder120 of the shuttle member 42. Similarly, a longitudinal proximal forceapplied to the tubular member 40 (e.g., when encountering an anatomicalstructure during a delivery procedure) is directly transferred onto theshuttle member 42 via the abutting interface between the proximal end 52of the tubular member 40 and the shoulder 120 of the shuttle member 42.In the presence of forces normally expected during a delivery procedure,once in the delivery state, the tubular member 40 will not moveproximally relative to the shuttle member 42, and the shuttle member 42will not move distally relative to the tubular member 40. The guideextension catheter assembly 20 can be transitioned from the deliverystate to a released state by applying a pulling force in the proximaldirection onto the shuttle member 42 while holding the tubular member 40stationary. In the released state, the shuttle member 42 is free ofdirect, physical connection with the tubular member 40.

Portions of an alternative guide extension catheter assembly 130 areshown in FIG. 7B and illustrate another example of complementaryconnection features of the present disclosure. The guide extensioncatheter assembly is 130 is arranged in a delivery state and includes atubular member 132 and a shuttle member 134. The tubular member 132 andthe shuttle member 134 can have any of the forms described in thepresent disclosure. In this regard, the tubular member 132 defines aproximal end 136 and a lumen 138 bounded by an interior face 140. Theshuttle member 134 includes a support section 142 and a trailing region144. The support section 144 defines a support surface 146 sized andshaped to be slidably received within the lumen 138 as described above.The trailing region 144 defines a ramp surface 148 and a shoulder 150.The ramp surface 148 extends proximally from the support surface 146,expanding in diameter toward the shoulder 150. Thus, an outer dimensionor diameter of the ramp surface 148 increases or expands in the proximaldirection, from a diameter less than a diameter of the lumen 138 at thesupport surface 146 to a diameter greater than the diameter of the lumen138 adjacent the shoulder 150. An outer dimension or diameter of theshoulder 150 can approximate or be greater than an outer diameter of thetubular member 132.

The complimentary connection features associated with the guideextension catheter assembly 130 include a configuration of a diameter ofthe lumen 138 at or proximate the proximal end 136, along with the rampsurface 148. With initial insertion of the shuttle member 134 into thelumen 138 via the proximal end 136, the shuttle member 134 is readilydistally advanced relative to the tubular member 132 due to clearancebetween the interior face 140 and the support surface 146. As the rampsurface 148 enters the lumen 138, the ramp surface 148 is brought intodirect, physical contact with the interior face 140 along those regionsof the ramp surface 148 having a diameter greater than the diameter ofthe lumen 138. In the delivery state illustrated in FIG. 6B, a taperedfit or connection between the ramp surface 148 of the shuttle member 134and the interior face 140 of the tubular member 132 has been obtained.In some embodiments, a material of the tubular member 132 compresses inresponse to forces exerted thereon by the ramp surface 148 with distaladvancement of the shuttle member 134 relative to the tubular member132. In other embodiments, a slight taper can be incorporated into adesign of the tubular member 132 at the proximal end 136, with thistaper angle approximating a taper angle of the ramp surface 148.

The direct, physical connection provided by the complementary connectionfeatures of the embodiment of FIG. 7B is such that a longitudinal distalforce applied to the push member 70 (otherwise attached to the shuttlemember 134) is directly transferred onto the tubular member 132 as adistal longitudinal force via the abutting interface between theinterior face 140 of the tubular member 132 and the ramp surface 148 ofthe shuttle member 134. Similarly, a longitudinal proximal force appliedto the tubular member 132 (e.g., when encountering an anatomicalstructure during a delivery procedure) is directly transferred onto theshuttle member 134 via the abutting interface between the interior face140 of the tubular member 132 and the ramp surface 148 of the shuttlemember 134. In the presence of forces normally expected during adelivery procedure, once in the delivery state, the tubular member 132will not move proximally relative to the shuttle member 134, and theshuttle member 134 will not move distally relative to the tubular member132. The guide extension catheter assembly 130 can be transitioned fromthe delivery state to a released state by applying a pulling force inthe proximal direction onto the shuttle member 134 while holding thetubular member 132 stationary.

Portions of another alternative guide extension catheter assembly 160are shown in FIG. 7C and illustrate another example of complementaryconnection features of the present disclosure. The guide extensioncatheter assembly is 160 is arranged in a delivery state and includes atubular member 162 and a shuttle member 164. The tubular member 162 cangenerally have any of the forms described in the present disclosure. Inthis regard, the tubular member 162 defines a proximal end 166 and alumen (hidden). Further, a slot 168 is formed through a wall of thetubular member 162, extending from and open to the proximal end 166. Theslot 168 can have a first segment 170 and a second segment 172. In someembodiments, the first segment 170 extends from the proximal end 166 ina generally longitudinal direction (e.g., parallel with a centrallongitudinal axis of the tubular member 162). The second segment 172extends from the first segment 170 opposite the proximal end 166,defining a non-parallel angle relative to the first segment 170. Forexample, an angle defined by the first and second segments 170, 172 canbe in the range of approximately 70-110 degrees, and in someembodiments, the second segment 172 extends in a circumferential fashionrelative to a circumference of the tubular member 162.

The shuttle member 164 can generally have any of the forms described inthe present disclosure. In this regard, the shuttle member 164 includesa support section 174 defining a support surface 176 and a post 178. Thesupport surface 176 is sized and shaped to be slidably received withinthe lumen (not shown) of the tubular member 162 as described above. Thepost 178 projects radially outwardly from the support surface 176 and issized and shaped to be slidably received within the slot 168.

The complimentary connection features associated with the guideextension catheter assembly 160 include a configuration of the slot 168and the post 178. With initial insertion of the shuttle member 164 intothe lumen (not shown) of the tubular member 162 via the proximal end166, the shuttle member 164 is readily distally advanced relative to thetubular member 162 due to clearance between the support surface 176 andthe tubular member 162. With continued distal advancement, as the post178 approaches the proximal end 166, the shuttle member 164 isrotationally oriented such that the post 178 is longitudinally alignedwith the slot 168 at the proximal end 166. With further distaladvancement, then, the post 178 will enter the slot 168 and progressalong the first segment 170. Upon reaching the transition from the firstsegment 170 to the second segment 172, the shuttle member 164 is rotatedrelative to the tubular member 162 such that the post 178 slides withinthe second segment 172 to the arrangement of FIG. 7C.

The direct, physical connection provided by the complementary connectionfeatures of the embodiment of FIG. 7C is such that a longitudinal distalforce applied to the push member 70 (otherwise attached to the shuttlemember 164) is directly transferred onto the tubular member 162 as adistal longitudinal force via the abutting interface between a structureof the tubular member 162 surrounding the slot 168 and the post 178 ofthe shuttle member 164. Similarly, a longitudinal proximal force appliedto the tubular member 162 (e.g., when encountering an anatomicalstructure during a delivery procedure) is directly transferred onto theshuttle member 164 via the abutting interface between the tubular member162 and the post 178 in a region of the slot 168. In the presence offorces normally expected during a delivery procedure, once in thedelivery state, the tubular member 162 will not move relative to theshuttle member 164, and the shuttle member 164 will not move relative tothe tubular member 162. The guide extension catheter assembly 160 can betransitioned from the delivery state to a released state by reversingthe above steps, such as rotating the shuttle member 164 relative to thetubular member 162 to move the post 178 to the first segment 172, andthen applying a pulling force in the proximal direction onto the shuttlemember 164 while holding the tubular member 162 stationary.

The guide extension catheter assemblies of the present disclosure can beuseful with a number of different procedures, such as procedures thatentail percutaneously accessing an intravascular target region. Withthese and other procedures, the guide extension catheter assemblies ofthe present disclosure can be provided to a clinician as part of acoronary treatment system that further includes a guide catheter and aninterventional coronary device. The guide catheter can have aconventional design. The interventional coronary device can be anydevice for treating, for example, an abnormal condition of a coronaryartery, such as, but not limited to, a stenosis. Non-limiting examplesof interventional coronary devices include guidewires, a catheter-basedtreatment device (e.g., a balloon catheter carrying an expandable stent,a catheter carrying a self-expanding stent, a fractional flow reserve(FFR) catheter), etc. In some embodiments, the coronary treatmentsystems of the present disclosure include at least one guidewire alongwith an additional or separate interventional coronary device that isnot a guidewire.

With reference to FIG. 8A, some methods of the present disclosure caninclude delivering a treatment device to a desired treatment location,such as in a coronary artery CA that is accessed through the aorta AA. Aguide catheter 200 can be utilized to access the aorta AA as shown.Generally, the guide catheter 200 includes a lumen sized to receive anauxiliary device or devices (e.g., a guide extension catheter assembly,an interventional coronary device, etc.). In some embodiments, aguidewire (not shown) can be deployed to assist in delivering the guidecatheter 200 to the general arrangement of FIG. 8A. Regardless, theguide catheter 200 is arranged such that a distal side 202 thereof is ator adjacent an ostium O of the coronary artery CA.

A guide extension catheter assembly of the present disclosure isarranged into the delivery state and advanced through the guide catheter200. For example, FIG. 8B illustrates a portion of the guide extensioncatheter assembly 20 in the delivery state and being advanced within alumen 204 of the guide catheter 200 that has otherwise been advancedthrough an intravascular passage 206 along with a guidewire 208. Thetubular member 40 is disposed over and supported by the shuttle member42, and the guidewire 208 is slidably received within the passageway 76of the shuttle member 42. Advancement of the guide extension catheterassembly 20 can be facilitated by a distal pushing forced applied by theclinician onto the push member 70. In some embodiments, an additionaldistal pushing force can be applied onto the shaft 50. Regardless, theshuttle member 42 provides mechanical and/or structural support to thetubular member 40 sufficient to facilitate delivery of the tubularmember 40 through a tortuous intravascular pathway (e.g., the pathway206 partially implicated by FIG. 8A).

With reference between FIGS. 8A and 8B, distal advancement of the guideextension catheter assembly 20 relative to the guide catheter 200continues, with the leading end 72 of the shuttle member 42 attainingand then advancing distally beyond the distal side 202 of the guidecatheter 200. The tubular member 40 and the shuttle member 42 thus passthrough the ostium O and enter the coronary artery CA. The optionaltapered tip section 84 of the shuttle member 42 promotes atraumaticcontact with tissue/walls of the coronary artery. As reflected by FIG.8C, distal advancement of the guide extension catheter assembly 20continues until the tubular member 40 is located at a desired positionrelative to the guide catheter 200 and the coronary artery CA (e.g., aportion of the tubular member 40 is within the guide catheter 200 and aremainder of the tubular member 40 extends along the coronary arteryCA).

With the tubular member 40 positioned as desired, the support device 32is removed from the patient. For example, a proximal pulling force isapplied by the clinician onto the push member 70 while at the same timea force resisting proximal movement is applied onto the shaft 50. As aresult, the shuttle member 42 is caused to retract proximally from thetubular member 40, and the tubular member 40 remains relativelystationary relative to the guide catheter 200 and the coronary arteryCA. Complete removal of the support device 32 is reflected by FIG. 8D,illustrating that the guide extension catheter 30, and particular thetubular member 40, has remained at the desired position.

The guide extension catheter 30 is then available to facilitate deliveryof an interventional coronary device 210 as generally shown in FIG. 8E.With reference between FIGS. 8D and 8E, the interventional coronarydevice 210 is delivered through the lumen 204 of the guide catheter 200and then advanced through the lumen 56 of the tubular member 40. Adistal working end of the interventional coronary device 210 (e.g., astent loaded over a balloon) is advanced distally beyond the distal end54 of the tubular member 40, and positioned as desired, for example totreat a stenosis 212. FIG. 8E further reflects that in some embodiments,the tubular member 40 can include or define perfusion holes 214.

The guide extension catheter assemblies, coronary treatment systems andmethods of the present disclosure provide a marked improvement overprevious designs. The shuttle member or delivery shuttle assists innavigating and delivering the guide extension catheter to the targetsite (e.g., diseased artery). Once in place, the delivery shuttle isremoved and the guide extension catheter is left in place to facilitatedelivery of additional devices such as a stent. As a purpose of thedelivery shuttle is to deliver the guide extension catheter, it can bedesigned to maximize deliverability of the device, thus sacrificing themechanical performance of the guide extension catheter if it was astandalone device. However, because the guide extension catheter is nota standalone device, it can be designed with specific or unique featureswell suited for a particular procedure such as multiple perfusion holesor a thinner wall to give a larger inner diameter/smaller outerdiameter.

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A guide extension catheter assembly comprising: aguide extension catheter including: a shaft, a tubular member defining aproximal end opposite a distal end and a lumen open to the proximal anddistal ends, wherein the shaft is coupled to the tubular member at theproximal end and extends proximally from the proximal end; and a supportdevice including: a push member, a shuttle member defining a leading endopposite a trailing end, wherein the push member is coupled to theshuttle member at the trailing end and extends proximally from thetrailing end; wherein the guide extension catheter assembly isconfigured to selectively provide a delivery state in which at least aportion of the shuttle member is disposed within the lumen, the leadingend is distal the distal end, and the shuttle member is directly,physically connected to the tubular member such that a longitudinaldistal force applied to the push member is transferred to the tubularmember as a longitudinal distal force via the shuttle member.
 2. Theguide extension catheter assembly of claim 1, wherein the guideextension catheter assembly is configured to further provide a releasedstate in which the shuttle member is free of direct, physical connectionto the tubular member.
 3. The guide extension catheter assembly of claim2, wherein the released state includes the shuttle member movingproximally from the tubular member in response to a longitudinalproximal force applied to the push member.
 4. The guide extensioncatheter assembly of claim 3, further comprising complementaryconnection features configured to selectively directly, physicallyconnect the tubular member and the shuttle member.
 5. The guideextension catheter assembly of claim 4, wherein the complementaryconnection features include a trailing segment of the shuttle memberforming a shoulder sized and shaped to abut the proximal end of thetubular member with distal advancement of the shuttle member through thelumen.
 6. The guide extension catheter assembly of claim 4, wherein thecomplementary connection features include a first ramp surface definedat an interior of the tubular member proximate the proximal end and asecond ramp surface defined at an exterior of the shuttle memberproximate the trailing end, wherein the ramp surfaces are sized andshaped to engage one another with distal advancement of the shuttlemember through the lumen.
 7. The guide extension catheter assembly ofclaim 4, wherein the complementary connection features include a slotformed in one of the tubular member and the shuttle member and a postcarried by the other of the tubular member and the shuttle member, andfurther wherein the post is sized and shaped to selectively nest withinthe slot.
 8. The guide extension catheter assembly of claim 1, whereinan outer diameter of the shaft is less than an outer diameter of thetubular member, and an outer diameter of the push member is less than anouter diameter of the shuttle member.
 9. The guide extension catheterassembly of claim 1, wherein a maximum outer diameter of the shuttlemember along at least a majority of the shuttle member including theleading end is not greater than a minimum diameter of the lumen.
 10. Theguide extension catheter assembly of claim 1, wherein a hoop strength ofthe shuttle member is greater than a hoop strength of the tubularmember.
 11. The guide extension catheter assembly of claim 1, whereinthe tubular member defines a plurality of perfusion holes.
 12. The guideextension catheter assembly of claim 1, wherein the shuttle memberincludes a tapering, atraumatic tip at the leading end.
 13. The guideextension catheter assembly of claim 1, wherein the shuttle memberdefines a passageway open to the leading end.
 14. A coronary treatmentsystem comprising: a guide catheter; a guide extension catheter assemblyincluding: a guide extension catheter including: a shaft, a tubularmember defining a proximal end opposite a distal end and a lumen open tothe proximal and distal ends, wherein the shaft is coupled to thetubular member at the proximal end and extends proximally from theproximal end, and a support device including: a push member, a shuttlemember defining a leading end opposite a trailing end, wherein the pushmember is coupled to the shuttle member at the trailing end and extendsproximally from the trailing end, wherein the guide extension catheterassembly is configured to selectively provide a delivery state in whichat least a portion of the shuttle member is disposed within the lumen,the leading end is distal the distal end, and the shuttle member isdirectly, physically connected to the tubular member such that alongitudinal distal force applied to the push member is transferred tothe tubular member as a longitudinal distal force via the shuttlemember; and an interventional coronary device.
 15. The coronarytreatment system of claim 14, wherein the guide catheter defines a lumensized and shaped to slidably receive the tubular member and the shuttlemember in the delivery state.
 16. The coronary treatment system of claim14, wherein the lumen of the guide catheter is sized to slidably receivea working end of the interventional coronary device.
 17. The coronarytreatment system of claim 14, further comprising a guidewire.
 18. Amethod of percutaneously accessing an intravascular target region, themethod comprising: positioning a distal side of a guide catheteradjacent to an ostium of a target vessel; arranging a guide extensioncatheter assembly to a delivery state, the guide extension catheterincluding: a guide extension catheter including: a shaft, a tubularmember defining a proximal end opposite a distal end and a lumen open tothe proximal and distal ends, wherein the shaft is coupled to thetubular member at the proximal end and extends proximally from theproximal end, and a support device including: a push member, a shuttlemember defining a leading end opposite a trailing end, wherein the pushmember is coupled to the shuttle member at the trailing end and extendsproximally from the trailing end, wherein the delivery state includes atleast a portion of the shuttle member disposed within the lumen, theleading end distal the distal end, and the shuttle member directly,physically connected to the tubular member such that a longitudinaldistal force applied to the push member is transferred to the tubularmember as a longitudinal distal force via the shuttle member; advancingthe guide extension catheter assembly in the delivery state through theguide catheter such that at least a region of the tubular memberprojects distally beyond the distal side; transitioning the guideextension catheter assembly from the delivery state, including removingthe support device from the guide extension catheter; and advancing aninterventional coronary device through the guide catheter and thetubular member.
 19. The method of claim 18, wherein the step ofpositioning includes sliding the guide catheter over a guidewire. 20.The method of claim 19, wherein the step of advancing includes slidingthe guide extension catheter assembly over the guidewire.